1. Field of the Invention
The present invention relates generally to electrical outlets having a guard against electrical shock and burn and, more particularly, to a cube tap having protective plates mounted thereon.
2. Description of the Prior Art
It has long been recognized that electrical outlets present a substantial hazard to children. Children are by nature curious and this curiosity leads them to insert metallic objects into prong-admitting passageways which lead to female contacts housed in a connector. Seeing their parents insert objects into electrical outlets and imitating them, children insert what they believe to be similar objects without realizing the dangers involved. As a result, they are shocked or burned, sometimes seriously and, upon occasion, fatally.
The increading concern for child safety has led to a safety requirement for cube taps of electrical cords. The requirement is that all, or all but one, of the pairs of prong-receiving slots of the cube taps be shielded or protected in some manner.
A number of devices have been devised for satisfying this requirement including pseudo-plugs of electrically non-conductive material which are plugged into the outlet in a manner analogous to that shown in U.S. Pat. No. 3,989,334.
Other approaches utilize a protective cover plate which is moved between a plug-blocking and a plug-receiving position by a spring. U.S. Pat. Nos. 4,094,569; 3,865,456; 3,068,442; 3,222,631; 2,820,842; 2,710,382; 2,477,803 are representative of constructions which utilize separate coil or leaf springs to slide a cover plate between the aforementioned positions.
Due to the fact that the constructions with separate springs utilize a multitude of parts and require great skill to assemble such connectors, it has been proposed in U.S. Pat. No. 3,810,070 to slide a protective cover plate directly against the elastomeric connector body itself. However, this construction is not entirely satisfactory in situations where the elastomeric material hardens due to age or due to cold temperatures. In such cases, the hard elastomeric body becomes so stiff due to the cold temperatures, that the user must exert a great amount of force to push the plate relative to the body. Another construction which eliminates separate springs is disclosed in U.S. Pat. No. 3,980,371. This patent teaches a slidable cover plate which has a one-piece spring mounted in a cavity of a connector body. Although generally satisfactory for its intended purpose, this cover has not proven to be altogether reliable in operation. First of all, the sliding movement of the cover generates a high degree of frictional drag, thereby generating a large magnitude force at the point of interconnection of the spring with the cover. This interconnection becomes progressively more stressed during repeated operation and eventually the interconnection is broken. Secondly, the spring has a very thin tip which engages a smaller flange in the cavity. It has been found that the spring does not remain in the cavity because it is not effectively restrained therein, since the tip slips off the flange by the force generated during the aforementioned sliding movement. Finally, the cover is not reliably registered in its end-limiting positions relative to the connector body.